//最长回文子串
//测试链接：https://leetcode.cn/problems/longest-palindromic-substring/
public class LongestPalindrome {
    public String longestPalindrome(String s) {
        int n = s.length();
        boolean[][] dp = new boolean[n][n];
        int begin = 0, len = 1; // 标记⼀下最⻓⼦串的起始位置和⻓度
        for (int i = n - 1; i >= 0; i--) {
            for (int j = i; j < n; j++) {
                if (s.charAt(i) == s.charAt(j))
                    dp[i][j] = i + 1 < j ? dp[i + 1][j - 1] : true;
                if (dp[i][j] && j - i + 1 > len) {
                    len = j - i + 1;
                    begin = i;
                }
            }
        }
        return s.substring(begin, begin + len);

    }
}
